Giant Ice Shelf Snaps

Popo writes "Sattelite images have revealed that an ancient 66 square-kilometer ice shelf, the size of 11,000 football fields, has snapped off from an island in Canada's arctic. The Ayles Ice Shelf was one of 6 major shelves remaining in Canada's arctic and is estimated to be over 3000 years old. The collapse was so powerful that earthquake monitors 250 km away picked up tremors. Scientists say it is the largest event of its kind in 30 years and point their fingers at climate change as a major contributing factor."

Re:Non Global-Warming Activity

[nharmon]

I mean the result of, RESULT OF! Oh good lord.

Re:How much is that in square furlongs?

[Tucan]

Ah Google, what can't you do?

66 (square kilometers) = 630.89552 square furlongs

Re:Drinks all around!

[butterwise]

Actually, a real good margarita [wikihow.com] consists of good tequila, fresh lime juice and triple sec - not a mix.

Re:How much is that in square furlongs?

[DrSkwid]

58 sq km

So a bit bigger than Bermuda [antor.org] (zoom out) [worldatlas.com] but a bit smaller than San Marino [aboutromania.com] (zoom out) [worldatlas.com]

Re:Well...

[Decaff]

that's my thought. a 1300 years ago it was so warm in England that english wine was better than french wine. I am not going to worry about Global warming until that happens again.

This is a very naive view. The problem is that most of our current civilization and infrastructure has been developed in the past few centuries during which the climate was not that warm. This infrastructure is fragile - it would not take much sea rise or change in rainfall patterns to cause major problems for a significant proportion of humanity.

You may not need to worry, but the hundreds of millions (if not billions) whose lives rely on our current climate would probably need to worry if things changed to the way they were 1300 years ago.

Re:How much is that in square furlongs?

[Ziest]

66 square kilometers == 25.5 square mile

About half the size of San Francisco

Re:11,000 Football field

[ROBOKATZ]

Rhode Island is 1214 square miles or 33844377600 square feet.
A football field is 58000 square feet x 11000 = 638000000 square feet for the iceberg.
Rhode Island is about 584524 football fields.

So the iceberg is about 1/53rd of the size of Rhode Island.

Re:Non Global-Warming Activity

[Alchemar]

The increase in radiation is caused by the hole in the ozone layer, but I think everything else is pretty much due to global warming.

Been There Done That

[sycodon]

Maybe he should have worked there longer. Follow this link.

http://pubs.aina.ucalgary.ca/arctic/Arctic39-1-15. pdf [ucalgary.ca]

In 1984 this study was done in Canada. The first page kind of says it all.

" Between 1959 and 1974 a total of 48sqkm calved off from Milne and Ayles ice shelves. In addition, the Ayles Ice Shelf moved about 5km out into Ayles Ford"

Not quite 66 sqkm but close. And it sounds as if the shelf broke off rather recently within a few decades, and somehow reattached itself. No mention of that in the story, but there is a significant emphasis that the ice is 3000 years old and ancient. Making it seem as if this has been the same for 3000 years. Next at the bottom left of the first page.

"The largest observed ice calving occurred at Ward Hunt Ice Shelf (just north of Ayles) where almost 600SQKM, broke off between 1961 and 1962.

Re:Well...

[Decaff]

So...even the researchers working on the issue say that they don't know if the cause is 'global warming', whatever that might be defined as, or something else. If the cause is the 'something else' then maybe the same thing happened 30 years ago, too.

No. You are misinterpreting scientific honesty. "Cannot definitively say" does not mean "don't know".

Re:Because we all know

[Decaff]

Puhlease.... It takes more than 20 years for ice this thick to melt to a shelving point.

No, it doesn't. All it takes is for some surface meltwater to percolate down through the ice. Below the ice, it can act as a lubricate, allowing fast movement.

English Vineyards

[enodo]

The English vineyards bit is a standard contrarian talking point. The problem is that (a) it's not clear that vineyards tell you anything about climate (rather than economics) and (b) at any rate there's far more wine growing in England now than there was in the past.

See the discussion here

http://www.realclimate.org/index.php/archives/2006 /07/medieval-warmth-and-english-wine/ [realclimate.org]

I have never seen a reference that claimed that English wine was "better" than French wine, so that seems to be new and made up.

Re:I can't wait.....

[ROMRIX]

.... for the anti global warming types to downplay that CLEARLY OBVIOUS FACT that global warming is the cause.

That is not the point, global warming is a fact, global warming is the cause of melting ice, global warming is the cause of warmer oceans. That is not what is being contested.
What is being contested is the cause of global warming. There are two podiums here, one is for arguing the cause is man made, the other is for arguing that it is a naturally recurring event.
The first has little evidence to support it other than (slightly) higher co2 levels in the atmosphere. The second of which has strong evidence recorded in, what else but the ice itself as well as in fossil records.
You cannot argue that there have been global warming events in the past but you can argue that man couldn't have been the cause then.
So I guess we are in agreement? Global warming is a CLEARLY OBVIOUS FACT.

Re:Well...

[naoursla]

Go watch Al Gore's documentary "An Inconvenient Truth". He presents data gathered by scientists that use ice core samples to infer temperature and CO2 cycles over the last 650,000 years. The data as he presents it is pretty compelling. If you choose, you can then do more research on your own to determine the veracity of that data, but it will help answer many of the questions you pose.

Re:Been There Done That

[xutopia]

Those historical figures are for small bits or simple melting. They aren't for large blocks the size of this one popping off.

" Between 1959 and 1974 a total of 48sqkm calved off from Milne and Ayles ice shelves. In addition, the Ayles Ice Shelf moved about 5km out into Ayles Ford"

"The largest observed ice calving occurred at Ward Hunt Ice Shelf (just north of Ayles) where almost 600SQKM, broke off between 1961 and 1962".

Re:How much evidence do we need?

[Aardpig]

How many vast Ice sheets have cracked recently?

I believe that the Larson A and B ice sheets, in Antarctica, broke up within the past decade.

Re:Huh?

[A beautiful mind]

We had global warming 30 years ago? I thought we were all supposed to fear global cooling back then.

Go thank the press for that. Scientists didn't say that there is global cooling, the press conjured the "theory" up.

What is the frequency of such events?

Note, this is scientists speaking. When they say "this is the largest event of its kind in 30 years", it is NOT equivalent with saying "last time an event like this happened was 30 years ago". They are only saying, that from the events in the last 30 years, this is the largest so far. They don't say anything about what happened 32, 35 or 3500 years ago, because they might not have the data to confirm that such event like this DIDN'T happen. It is entirely possible that such event didn't happen in the last 2000 years, but then you have to verify or falsify this assumption with evidence.

Re:Non Global-Warming Activity

[Anonymous Coward]

Seriously, is there anything happening in the arctic or antarctic regions that IS NOT the [result] of Global Warming?

No. Without global warming, the arctic and antarctic ought to be stable on human timescales. The fact that there is anything happening down there at all is bad news.

Re:less ambiguous units please!

[QRDeNameland]

66 km^2 is about 2% of Rhode Island since it is about 3,144 km^2. But if you are trying to make it sound big, your measuring stick should definitely be _smaller_ than what your measuring.

A better "island" for comparison would be Manhattan [wikipedia.org], which is 51 km^2 (making the broken ice shelf around 25-30% larger than Manhattan Island). Not only is it a unit which is quite close to the area in question, it is also a place where many people actually might have a decent feel for how big that is.

Re:Geography lesson

[gronofer]

Not, they do not meet at the tropics.

Penguins live on the equator at Galápagos, although this doesn't invalidate your statement.

Re:Non Global-Warming Activity

[Anonymous McCartneyf]

I thought we closed that hole in the ozone layer a decade ago!

Re:Drinks all around!

[Anonymous Coward]

lime is sour, not bitter

Re:Drinks all around!

[budgenator]

the bitter comes from the membrane around the sections in citrus fruit, you can take a grapefruit sections, peel off the membrane from the sections and the remaining fruit is surprisingly sweet and not at all bitter. I often eat grapefruit that way, like most people eat oranges.

Re:Do you live in the mountains or something?

[Xiroth]

Even during the winter snow is extremely rare in the lowlands (last time it snowed here in Melbourne - at the southeast corner of the mainland - was last year, but the time before that was a couple of decades ago {source [smh.com.au]]}). During summer, there's generally no snow anywhere. The snow that fell in the mountains is what is generally associated with the middle of winter (in fact, last winter there was next to no snowfall), so after days of heat (around 100F) that allowed the spread of fires so bad that smoke covered pretty much the entire state, the snow was highly strange (if welcome for the firefighters, as it allowed them to be home for Christmas).

Why do melting icebergs raise sea level?

[Wills]

The pure water from a melting iceberg is less dense than sea water. How much less dense depends on temperature. The water from a melting iceberg will probably be around 1Celsius. Pure water at 1C is 2.5% less dense than sea water at 1C. [csgnetwork.com]

Imagine you could contain the pure water from a fully melted iceberg inside a sphere. In the same way an iceberg floats and sticks out of the sea, the ball of pure water would float in the sea with 2.5% of its volume sticking out above the sea surface. If you let the water out of the sphere, the 2.5% volume of pure water that was above the sea level inside the sphere will spread out across the planet's oceans, raising the global sea level.

The iceberg mentioned in the article was 40metres thick and 66 square kilometres in area, so the ice volume is 2.6 billion cubic metres. Ice is 8.3% less dense than pure water liquid [wikipedia.org], so when the iceberg melts, the volume of pure water will be 2.4 billion cubic metres and 2.5% of that is 60 million cubic metres. The world has 360 million square kilometers of ocean [www.cnes.fr], so adding 60 million cubic metres of pure water will raise average global sea level by 0.17 microns (thousandths of a millimetre)!

Re:Drinks all around!

[wizzat]

I don't think it matters... [google.com]

Re:Well...

[shalmaneser1]

correction: the medieval warm-period at its hottest ~1000ad was colder than now.
certain isolated geographical may have been warmer ( eg. england ) but the average global temp at the time was at about the same temp as the 1970s.
right now is the warmest period on record for a long time.

oh. and england started growing grapes for wine last year.

http://www.realclimate.org/index.php/archives/2004 /12/werent-temperatures-warmer-during-the-medieval -warm-period-than-they-are-today/ [realclimate.org]